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    <title>Document</title>
    <script>
        console.log(0.1 + 0.2);//0.30000000000000004
        console.log(0.07 * 100);//7.000000000000001
        var num = 0.1 + 0.2;
        console.log(num == 0.3);//flase 不要直接判断浮点数是否相等
    </script>
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    <!-- 
        + 0.1+0.2=0.30000000000000004二进制计算浮点会有误差，尽量避免
        -
        *
        / 不是取商，可以直接返回小数
        % 取余
     -->
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